The genetic analysis of aging has revealed pathways that can extend lifespan throughout the animal kingdom. But how these longevity pathways can be activated by natural cues, how they coordinate the rate of aging among the tissues, and how they ultimately influence cellular aging, are still not well understood. This information is vital,as it could suggest new ways to keep us healthy, youthful and disease-free for a longer time. Twenty years ago, our lab discovered that genes now known to encode an insulin/IGF-1 receptor and a FOXO transcription factor can slow aging and double the lifespan of C. elegans. Since that time, this grant's funding has allowed us to advance our understanding of this pathway substantially, and to discover new longevity pathways as well. During the next funding period, we will address key, unanswered questions about aging, building on discoveries from this grant. 1. How are longevity pathways regulated in nature? We have found that specific chemosensory circuits control C. elegans' aging, at least in part, by regulating FOXO activity. Because neurons are known to influence insulin/IGF-1 signaling and lifespan in mammals, using powerful new imaging and genetic approaches, we will ask how this C. elegans neurosensory circuit operates, and how it activates FOXO within the body. 2. We have found that once FOXO has been activated in a single tissue, it can slow the aging of other tissues by activating FOXO-independent longevity pathways. What are these downstream pathways? Our findings suggest that lipids play a key role. We will test this hypothesis, and identify additional downstream signaling components. 3. A key unanswered question is to what extent different longevity pathways converge on the same downstream cellular processes, and whether they regulate these downstream processes in distinct or common ways. We will use genetic and genomic techniques; coupled with a powerful new bioinformatics method we have developed, to address this question. 4. Finally, using biomarkers of aging we have identified, we will dissect a natural anti-aging process; cellular rejuvenation, and ask to what extent known longevity factors mediate this processes.